Footwear is worn on the feet so that a wearer can stand on the ground or walk. When a wearer walks with the footwear on, a so-called “three-beat rhythm” walking method is widely known to be the most preferable walking method. This walking method is performed as if a wearer rolled forwards while his or her sole contacts the ground in the sequence of the heel, the center of the foot, and the toes, in the state where the wearer stretches his or her backbone and leans his or her head slightly backwards.
In order to maintain such a three-beat rhythm walking method, Korean Patent No. 239854, which was filed in 1998 and is entitled “Footwear For Promoting Health” was proposed. According to the cited document, the footwear includes an outsole which has front and rear inclination parts that are inclined upwards at anterior and posterior portions of the bottom of the outsole, an upper which is attached to the upper portion of the outsole and protects the foot, and front and rear grooves which are formed in the front and rear inclination parts. The front and rear inclination parts, which are formed on the anterior and posterior portions of the footwear, allow a wearer to naturally walk in a three-beat rhythm.
The conventional footwear is constructed so that the outsole contacts the ground in the sequence of the rear inclination part, corresponding to the heel, the bottom part, corresponding to the center of the foot, and the front inclination part, corresponding to the toes. However, the conventional footwear is problematic in that it cannot satisfactorily absorb shocks applied by a walker's weight, so that the shocks are directly transmitted to the walker, and thus he or she may suffer pain in the ankle, the calf, the knee joint, or the thigh, and his or her fatigue may be increased.
Particularly, according to the prior art, an iron piece made of a metal material is inserted into the outsole so as to maintain the overall shape of the outsole. However, such an iron piece undesirably increases the severity of shocks transmitted to a walker.
Further, the conventional footwear is problematic in that the rear inclination part comprises a flat horizontal plane, so that all of a walker's heel contacts the ground at one time, thus a walking rhythm is interrupted, and the ankle, the calf, the knee joint, and the thigh are overstrained.
Moreover, when three-beat rhythm walking, it is preferable that the toes contact the ground in the sequence from the little toe to the big toe. However, the conventional footwear is problematic in that the front inclination part comprises a flat horizontal plane, so that it is impossible to make a walker's toes contact the ground in the sequence from the little toe to the big toe.